JAVASCRIPT的MVC示例
/** * The Model. Model stores items and notifies * observers about changes. */function ListModelthis._items = items; this._selectedIndex = -1; this.itemAdded = new Event(this); this.itemRemoved = new Event(this); this.selectedIndexChanged = new Event(this);}ListModel.prototype = { getItems : function return [].concat(this._items); }, addItem : function this._items.push(item); this.itemAdded.notify({ item : item }); }, removeItemAt : function var item; item = this._items[index]; this._items.splice(index, 1); this.itemRemoved.notify({ item : item }); if (index === this._selectedIndex) { this.setSelectedIndex(-1); } }, getSelectedIndex : function return this._selectedIndex; }, setSelectedIndex : function var previousIndex; previousIndex = this._selectedIndex; this._selectedIndex = index; this.selectedIndexChanged.notify({ previous : previousIndex }); }};Event is a simple class for implementing the Observer pattern:
function Eventthis._sender = sender; this._listeners = [];}Event.prototype = { attach : function this._listeners.push(listener); }, notify : function var index; for (index = 0; index < this._listeners.length; index += 1) { this._listeners[index](this._sender, args); } }};The View class requires defining controls for interacting with. There are numerous alternatives of interface for the task, but I prefer a most simple one. I want my items to be in a Listbox control and two buttons below it: "plus" button for adding items and "minus" for removing selected item. The support for selecting an item is provided by Listbox's native functionality. A View class is tightly bound with a Controller class, which "... handles the input event from the user interface, often via a registered handler or callback" (from wikipedia.org).
Here are the View and Controller classes:
/** * The View. View presents the model and provides * the UI events. The controller is attached to these * events to handle the user interraction. */function ListViewthis._model = model; this._elements = elements; this.listModified = new Event(this); this.addButtonClicked = new Event(this); this.delButtonClicked = new Event(this); var _this = this; // attach model listeners this._model.itemAdded.attach(function this.rebuildList(); }); this._model.itemRemoved.attach(function this.rebuildList(); }); // attach listeners to HTML controls this._elements.list.change(function this.listModified.notify({ index : e.target.selectedIndex }); }); this._elements.addButton.click(function this.addButtonClicked.notify(); }); this._elements.delButton.click(function this.delButtonClicked.notify(); });}ListView.prototype = { show : function this.rebuildList(); }, rebuildList : function var list, items, key; list = this._elements.list; list.html(''); items = this._model.getItems(); for (key in items) { if (items.hasOwnProperty(key)) { list.append($('<option>' + items[key] + '</option>')); } } this._model.setSelectedIndex(-1); }};/** * The Controller. Controller responds to user actions and * invokes changes on the model. */function ListControllerthis._model = model; this._view = view; var _this = this; this._view.listModified.attach(function this.updateSelected(args.index); }); this._view.addButtonClicked.attach(function this.addItem(); }); this._view.delButtonClicked.attach(function this.delItem(); });}ListController.prototype = { addItem : function var item = window.prompt('Add item:', ''); if (item) { this._model.addItem(item); } }, delItem : function var index; index = this._model.getSelectedIndex(); if (index !== -1) { this._model.removeItemAt(this._model.getSelectedIndex()); } }, updateSelected : function this._model.setSelectedIndex(index); }};And of course, the Model, View, and Controller classes should be instantiated. The sample, which you can below, uses the following code to instantiate and configure the classes:
$(function var model = new ListModel(['PHP', 'JavaScript']), view = new ListView(model, { 'list' : $('#list'), 'addButton' : $('#plusBtn'), 'delButton' : $('#minusBtn') }), controller = new ListController(model, view); view.show();});?<id="list" size="10" style="width: 15em"></<<id="plusBtn"> + </<id="minusBtn"> - </button>